1. What is cancer?

Due to damaged DNA, cancer begins when cells start to grow out of control. Healthy body cells grow, divide and die without incident, especially early in life. Upon adulthood, most cells divide only to replace those that have been injured or died. Cancer cells differ from healthy body cells in their persistent growth and division (American Cancer Society, “What Is Cancer?”). Thus, they outlive healthy cells and continue to form new, abnormal cells, which gather in masses of tissue called tumors and spread to other parts of the body (Genetic Science Learning Center). When the DNA in healthy cells is damaged the cell typically dies, but since the damaged DNA in cancer cells goes unrepaired, the deformity can be inherited. Each type of cancer is very different. They behave differently, grow at different rates and respond uniquely to separate treatments.

For more information, visit the American Cancer Society.

2. How many people are affected by breast cancer?

Breast cancer is the most common cancer among American women. It accounts for 32 percent of all cancers in women, and it is the leading cause of cancer deaths in women 35 to 54 years of age. Approximately one in nine women will develop breast cancer in her lifetime, and an estimated 215,000 women will be diagnosed with various stages of breast cancer in 2004. To date, over 2 million cases of breast cancer have been diagnosed and treated in the United States (American Cancer Society, "What Are the Key Statistics for Breast Cancer?").

3. What are the risk factors for breast cancer?

According to the National Cancer Institute and the American Cancer Society, identifiable risk factors for breast cancer exist. Gender and age are the primary indicators, as women are about 100 times more likely than men to develop breast cancer, and nearly 80 percent of women diagnosed with breast cancer are over 50 years old. In addition, a personal history of breast abnormalities, such as ductal carcinoma in situ and lobular carcinoma in situ, is linked to subsequent development of invasive breast cancer. Women whose first full-term pregnancy occurs after age 30 and women who never give birth are also at risk. Race seems to play a role in breast cancer, as white women are at a greater risk for developing the disease, while Black women are more likely to die of it. Certain behavioral characteristics, including smoking, alcohol consumption and high-fat diets are also implicated in the development of breast cancer.

For more information, visit A NewsHour with Jim Lehrer.

4. What is the genetic connection to breast cancer?

Recent studies suggest that 10 to 15 percent of breast cancer cases are hereditary. Furthermore, having one first-degree relative, such as a mother, sister or daughter, affected by breast cancer doubles a woman’s risk, and having two first-degree relatives multiplies that risk by five. In the 1980s, scientists discovered two genes that appear to be influential in the development of breast cancer, BRCA1 and BRCA2. BRCA1, a gene on chromosome 17, is known to be involved in tumor suppression, and BRCA2 is located on chromosome 13. Of the 10 to 15 percent of hereditary breast cancers, mutations of these two genes account for one-third of the cases, and they are significantly linked to early-onset breast cancer. The risk of breast cancer increases with additional occurrences and decreasing age at onset of affected relatives (Loman et al. 175).

5. What are available screening options?

A variety of screening options are available to women. The most popular and regularly used practices include breast self-exams (BSEs) and mammographies. Additionally, breast MRIs are in the early stage of testing but not yet ready for routine use. While no test is perfect and these tests can result in incorrect readings, mammographies are the best tool for the early detection of breast cancer (Palo Alto Medical Foundation). In fact, women who performed BSEs before their breast cancer diagnosis were more likely to identify a small tumor and less likely to experience cancer in other parts of the body at the time of diagnosis. Most importantly, BSEs lower the rate of death from breast cancer (Cohen). Upon discovery of the BRCA1 and BRCA2 gene mutations, additional genetic screening options were developed. Today, blood tests exist to detect these gene mutations, and positive test results can lead to fairly accurate estimations of a woman’s risk of developing breast cancer (Palo Alto Medical Foundation).

5. Who is a candidate for genetic screening?

A list of criteria developed by the U.S. Preventative Services Task Force identifies guidelines to aid in that determination. First, the population screened must be at significant risk of suffering. For example, while 0.2 percent of the general population maintains a BRCA mutation, over 2 percent of Ashkenazi Jewish women possess such a change. Thus, this Jewish population certainly carries the significant burden discussed. Next, the committee recommends that there be an asymptomatic period during which the disease can be detected and that the screening procedure must be accurate during this period. In addition, the available screening test must be acceptable to the patient, and preventative intervention must surpass conventional physician follow-up practices. Thomas C. Rosenthal, M.D. and Stirling M. Puck, M.D. further recommend that “women who have a family history of breast cancer under age 50, two first-degree relatives with the disease, a male relative with breast cancer, or ovarian cancer in relatives under age 50 are at increased risk for carrying a BRCA1 or BRCA2 mutation, and these women should be offered genetic counseling.”

The test costs around $2,500, and it is currently estimated to detect 60 percent of the possible BRCA mutations.

For more information, visit the Genetic Science Learning Center or read this article from American Family Physician.

6. What do the results of genetic screening really mean?

If genetic screening is determined to be the appropriately aggressive form of early detection, all attempts should be made to test the breast cancer-affected woman first. If she caries the BRCA gene mutation, then subsequent relatives should be tested. Assuming the affected woman possesses a BRCA mutation and the unaffected woman does not, the unaffected woman was lucky not to inherit the mutation. Since a gene abnormality is ruled out in the unaffected woman, she is at the same risk of developing breast cancer as the general population. If the unaffected woman is also positive for a BRCA gene mutation, she may have up to an 85 percent chance of developing breast cancer, and she should continue intensive monitoring and consider preventative measures. If both the affected and unaffected women are BRCA negative, risk estimations are less accurate. It is possible that the family carries BRCA gene mutations that are not yet detected by testing procedures. The unaffected woman should also maintain intensive monitoring practices.

For more information, visit the Palo Alto Medical Foundation.

7. Are there any preventative measures?

Certain preventative measures solely reserved for women of significantly high risk are also being studied. High-risk women can consider taking a medication to block the effect of estrogen in the breast or breast removal. Drugs called Selective Estrogen Receptor Modifiers (SERMs) reduce the risk of breast cancer by up to 45 percent, and double mastectomy, which is often unnecessarily invasive and deforming, reduces the chance of developing breast cancer up to 90 percent (Palo Alto Medical Foundation). Tamoxifen is the most popular SERM drug used in the prevention of breast cancer. Although doctors have been prescribing the drug for other uses for more than 20 years, it has recently been explored as breast cancer-preventative therapy. The Breast Cancer Prevention Trial, conducted by the National Surgical Adjuvant Breast and Bowel Project and the National Cancer Institute, showed that women aged 35 and older who took a daily dose of tamoxifen for up to five years recorded 49 percent fewer cases of invasive breast cancer than those taking a placebo. In the group aged 35-49, side effects were minimal and occurred at a similar rate to the placebo group. Thus, tamoxifen can be taken as a preventative measure without serious side effects for young, high-risk women. Women in the Trial aged 50 and older, however, significantly raised their chances of developing both uterine cancer and blood clots in their lungs or major veins (National Cancer Institute).

For more information, visit the National Cancer Institute.